Analysis of advanced features of the Arm Cortex-M23 processor core

U ovom radu opisana je i analizirana procesorska jezgra ARM Cortex-M23 napisana u verilog jeziku za opis sklopovlja i implementirana u simulacijskom okruženju SimVision. Naglasak je stavljen na objašnjenje i testiranje naprednih sigurnosnih značajki omogućenih ekstenzijom TrustZone. Sustav je inicijaliziran i podijeljen na sigurni i nesigurni način rada. Prikazom signala u stvarnom vremenu prilikom izvršavanja simulacije omogućen je uvid u unutarnji rad jezgre te sigurnosne mehanizme. Korištenjem gotove biblioteke „Tiny AES in C“ implementiran je primjer sigurnog ugradbenog računalnog sustava za enkripciju ili dekripciju teksta pomoću ECB, CBC ili CTR načina rada po AES standardu iskoristivog u stvarnom svijetu.This paper deals with the description, analysis and an example of the advanced features available in the ARM Cortex-M23 processor core. The core is provided in verilog and implemented in the Cadence simulation environment SimVision. The paper focuses on studying and testing of the cores security features implented through the TrustZone security extension. The embedded system is divided into a secure and unsecure state and then initialized. By observing the processor signals in the simulation, a comprehensive insight is gained into the inner workings of the security mechanisms. A secure program example for AES encryption and decryption in a real-time embedded system is implemented through the use of the „Tiny AES in C“ external software library which supports CBC, EBC and CTR modes of operation. The example shows a low-cost, low-power secure encryption system ready for real world use